Wireless communications systems, for example packet based communications systems, may provide voice telephony using the Voice-over-Internet-Protocol (VoIP). Any historical demarcation between “data” and “voice” has become blurred in packet based communications systems such that the term “data” usually signifies payload information for any service, whether voice, or data such as may be provided by downloading from the Internet.
Differences remain however, in that voice will generally employ smaller packet sizes, for example due to delay sensitivity, than would traditional so-called data. For, example a non-voice data packet may be larger than a kilo-byte while a voice packet may be only approximately 15 to 50 bytes depending upon the vocoder rate employed.
Because of the smaller packet sizes utilized by voice sessions, a greatly increased number of voice users may be served thereby placing a burden on the control mechanisms and resources of the communications system.
For example, multiple voice users may form a group that shares a common control channel for allocating specific time-frequency resources, that is, traffic resources, to the multiple users. However, there is a possibility that some users in the group may not receive, or be able to correctly decode, the control channel information due to various reasons such as radio shadowing or fading. A possible solution may involve providing temporary, but specific control resources to a user that has not received a previously transmitted control message. However, such control resources require additional processing and transmission and therefore consumes even more resources which would have been available for voice traffic thus further burdening the network.
Thus, there is a need for handling mobile stations that have failed to receive a control message, without significantly increasing the overhead of the communication system.